Solenoid construction



Feb. 13, 1962 H. Y. FISHER SOLENOID CONSTRUCTION 2 Sheets-Sheet 1 Filed June 12, 1959 INVENTOR:

HARDiN Y FISHER BY W J M4 M ATT'YS Jill Q Feb. 13, 1962 H. Y. FISHER ,456.

SOLENOID CONSTRUCTION Filed June 12, 1959 I 2 Sheets-Sheet 2 FIG. 4 PRIOR ART F|G.6 PRIOR ART I30 I I I 1 [ram 27 2B INVENTOR: HARDIN Y. FISHER ATT'YS of the solenoid.

United States Patent SOLENOID CONSTRUCTION Hardin Y. Fisher, Hillside, Ill., assignor to Albert F. Dormeyer, Chicago, Ill.

. Filed June 12, 1959, Ser. No. 820,045

4 Claims. (Cl. 317191) This invention relates in general to solenoids, and more particularly to improvements in alternating current solenoids, to enhance their life. Still more particularly, this invention relates to improvements in plunger'and plunger slide structure construction. l

The present invention deals with improvements in the solenoid generally known in theindustry as a .T-bar plunger type solenoid, wherein the solenoid includesan elongated stem and a transversely extending bar at one end of the stem for use in a substantially C-shaped frame. This bar may be defined as. a cross bar or seating bar. More particularly, the improvements are applicable to the external reluctance solenoid disclosed in applicants copending application Serial No.795,261,

Patented Feb. 13, 1962 7' "FIG. 2 is an enlarged perspective view of the plunger and slides removed from the solenoid frame and constructed in accordance ;with the present invention;

.FIG. 3 is a viewtaken tirough the solenoid coil of FIG. 1 and showing the plunger slide'rails as extending into the'notches provided. in the plunger, with some parts f in section and broken away for purposes of clarity;

.FIG. 4 is an enlarged, fragmentary and partiallysectional view of the plunger and guide structure. of the prior art, wherein the plunger is shown in seated or contracted'position relative tothe plunger slides;

FIG. ,5 is a view similar to FIG. 4, but illustrating the present invention, and showing .the difference in filed February 24, 1959, although it 'will be appreciated that the present invention may be utilized in other types of solenoids.

In a solenoid of the type above mentioned, the plunger is slidably guided in a pair of spaced non-permeable slides mounted within the frame and the hollow center of the coil. These slides are provided with rails for containing movement of the plunger stem. When the plunger is in the extended or protracted position, wear is caused on the outer ends of the rail still engaging the I plunger to the extent that subsequent failure of the sole.-

noid. is caused by freezing of the plunger. At the or of less length than the cross bar. Because of this external reluctance 'bar, the slide, rails must terminate at a point slightly inward from the external reluctance bar in order to prevent interference in seating ,of the plunger. r i a The present invention consists of providing slots or notches in the external reluctance barto accommodate the outer free ends of the ,slidevrails, wherein the slide rails may be .made longer .andthereby provide -.greater support to the plungerinitsextended position.

Accordingly, it is an object of" this invention topro- *vide an improved solenoidhaving aplunger 'and plunger Slidestructure constructionwhi'chwill enhance the life A further object'oftliis invention resides in thepro; visionpt extending the life of a solenoid without-jn creasing thelcost'oflmaking thetsolenoid. Afstill further objectcfthisinvention is in the pro? underside of the plunger crossbar, an externalreluctance bar is provided having a dimension of less width the longer rails. a

length of the, plunger slide. rails;

FIG. 6 is a view of a plunger similar to that of FIG.

4 and of the prior art and illustrating the plunger in extended or protracted position; and

FIG. 7 is .a view similar to FIG. 6showing the plunger in extended or protracted position, but of. the present invention and ,illustratingin comparison the greater support provided for the plunger in extended position by 'To illustrate the invention,- the drawings showv the solenoid of the present invention as including generally a coil 10 having a plurality of turns carried on an insulating spool or bobbin, and a pair of terminal lugs 11 for connection to an electrical source. A generally C-shaPed laminated, permeable frame 12'embraces the coil 10, and has an opening at one endfor receiving a pair of spaced non-permeable slides13 and a generally T-shaped plunger 'The 'frame'12 is constructed: in the usual mannerby securing together a plurality of identically formed laminae 15. "The stack of laminae is covered on opposite sides by a specially formed lamina 16, having spaced apart flanges '17 and 18 struck out therefrom for providing support and positioning of the coil 10. The flanges 17 and 18 are ,cut away or notched at their inner edges 19' to provide clearance for receiving the identical but opvision of a plunger for ,a' solenoid having an elongated sternwith a cross barat one end and inwardly extending projections definingslots with a stem for freely re- K I 'ceiving the outer ends of the slide rails of the slide structure.

he r i fea u es. and advantages of th invention will'be apparent, ,from,the following d t il d i closure, taken in c njunction. with th acco panyi fdrawinss hcr l 'k refer n n mer ls efer s to like parts in which: 7 FIG. lis a perspective view of a solenoid embodying the present invention;

positely facing'plunger slides .13. p

As noted particularly in FIG. 3, the ;C-shaped.frame 12 includesparallel spaced legs 26 and 2 1 straddling the coil 10, and being connected together at adjacent ends by the high 22 of the frame. At the other ,end arms legs 20 and, inwardly extending-projections-Z3and 24 pec e y ep videdxw h ha e subs an y t e same cross section as the legs of the frame. Narrow pr jec io s 25 n i -ten'd inw rd y from th p io s 23 fin ldiy s psc ive yy fi t ths g w received. 7 w

T c p u g r 4. i cludes g nsral y a p r ty of identically formed 1 laminae secured together and defining an elongated stern 27, a transvrsely extending seating, bar or cross bar 28 arrangedat one end of the] stern, and an an'air gapor opening through which the plungerst'eingis external reluctance ban 29 securedLto the under side of The plunger 14 is constructed of a plurality of identically formed laminae 32 having pull bars 33 arranged over the outer laminae, and the pull bars and laminae are held together by suitable fastening members such as rivets 34. The seat'ng bar 28 of the plunger seats against the outer faces 35 of the C-frame when in closed position. The seating bar 28 includes seating surfaces or areas 36 which contact the outer faces 35 of the frame when the plunger is in seated position. The seating or cross bar 28 is generally rectangular in shape, and the external permeable bar 29 is also generally rectangular in shape and integral with the seat ng bar 28 and adjacent the under or inner side thereof. The permeable bar 29 is longer than the frame opening but of much less length than the seating bar 28, and sized to be freely received between the spaces 31 of the frame. It may be noted that when the plunger is seated as seen in FIG.

3, the plunger and frame are constructed so that the inner ends of the permeable bar 29 cannot contact the projections 25 and 26.

Referring now particularly to FIG. 2, it is seen that each slide includes a main body 37 having a pair of spaced plunger supporting rails 38 extending perpendicularly from opposite edges thereof and extending nearly the entire longitudinal length of the body, thereby defining a more or less channel-shaped slide. At the lower end of each slide, the plunger supporting rails 38 terminate at 33 so that the main part of the body may be arranged along the outer sides of the C-shaped frame as is seen in FIG. 3, and the terminal end 39 of the rails abuts against the inner side of the bight 22. The rails 38 extend substantially perpendicular to the body 37. A portion of the rails 38 is cut away at the upper end to provide clearance for the seating bar 28 and the permeable bar 29. The width of the ml 38 is sufiicient to give adequate support to the plunger stern, and gene ally equal to the thickness of a pull bar 33 and two or three laminae 32. Where the supporting rails 38 are cut away at the upper end, a very narrow supporting flange 40 is formed which has a width slightly less than the width of a pull bar 33 to further give support to the plunger along opposite sides of the plunger inasmuch as the pull bar extends the full length of the plunger. Accordingly, the upper terminal edges or ends of the rails, as indicated at 41, must be slightly spaced from the plunger permeable bar 29 when the plunger is in seated position.

In forming the slides 13, a stamping and punching operation is generally utilized, wherein the slides may be stamped and punched from a piece of material to the required configuration, and with some parts punched out as waste. Thus, the portions punched away at the upper and lower ends of the slide to define the terminal ends 39 and 41 of the rails would constitute waste material.

In order to best illustrate the present invention, FIGS. 4 and 6 disclose the prior art, wherein FIG. 4 shows the plunger relative to the slide in closed or seated position, while FIG. 6 shows the plunger relative to the slide in extended or protracted position. The parts to the plunger and slide in FIGS. 4 and 6 are numbered identically to that of the present invention-and already covered, but sufiixed b the letter a.

FIGS. and 7 represent the construction of the present invention and illustrate clearly the difference in structure over the prior art of FIGS. 4 and 6.

Slots or notches 42 are formed in the permeable bar 29, and open toward the lower end of the stem-27, and define projections 43 extending from the under side of the seating bar 28, as seen in FIGS. 2, 3, 5 and 7.

As seen in FIG. 5, the upper terminal ends 41 of the rails 38 are received freely within the notches or slots 42 of the plunger. It may be seen that the rails 38 of the present invention are longer than the rails 38a of the prior art as shown in FIGS. 4 to 7. Further, in comparing the extended positions of the pluugers, as in 4 FIGS. 6 and 7, it is noted that the plunger of the present Invention has a greater rail support by the longer rails than the plunger of the prior art in FIG. 6. This extension of the rails 38 enhances the overall life of the solenoid, but adds nothing to the cost of making the solenoid inasmuch as the portions of the rails normally removed from the slides of the prior art only constitute waste, and is done by a punching or s'milar operation. Further, the laminae 32, which make the plunger, are formed from a single stamping operation, and therefore it does not require any extra machining or labor cost.

From the foregoing, it will be appreciated that the plunger and slide construction of the present invention is such as to enhance the life of a solenoid without increasing the cost thereof.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, but it is understood tthat this application is to be limited only by the scope of the appended claims.

The invention is hereby claimed as follows:

1. In a solenoid, a coil with a hollow center, a substantially C-shaped frame embracing said coil having a narrow opening at one end aligning with the hollow center of the coil, a plunger slide structure including a pair of spaced non-permable slides arranged in the opening of said frame and the hollow of the coil, said slides having plunger supporting rails and a plunger, said plunger having an elongated stem reciprocable in said slides and guidably supported by said plunger supporting rails, a transversely extend'ng bar at the outer end of said stem, and projections extending from said bar along opposite sides of the stem defining slots for freely receiving the outer free ends of said rails which are of sufficient length to extend into said slots when the plunger is in seated position.

2. In a solenoid, a col having a hollow center, a substantially C-shaped frame embracing said coil having a narrow opening at one end aligning with the hollow center of the coil, a plunger slide structure including a pair of spaced non-permeable, channel-shaped slides arranged inthe opening of the frame and the hollow of the coil, said slides having plunger supporting rails, a substantially T-shaped plunger, said plunger comprising an elongated stem reciprocable in said slides, a transversely extending bar at the outer end of the stem, and projections extending from said bar toward the free end of the stem along opposite sides of the stern defining slots for freely receiving the outer free ends of the plunger supporting rails, said ra'ls being of sufiicient length so that they extend into said slots when the plunger is in seated position.

3. In a solenoid, a coil having a hollow center, a substantially C-shaped frame embracing said coil having a narrow opening at one end aligning with the hollow center of the coil, a plunger slide structure including a pair of spaced non-permeable, channel-shaped slides arranged in the opening of the frame and the hollow of the coil, said slides having plunger supporting rails, a substantially T-shaped plunger, said plunger comprisng an elongated stem reciprocable in said slides, a transversely extending bar at the outer end of the stern, and projections extending from said bar toward the free end of the stem along opposite sides of the stem defining slots for freely receiving the outer free ends of the plunger supporting rails, the supporting rafls being of such a length as to extend into said slots in said plunger substantially the entire depth thereof when the plunger is in seated position.

4. In a solenoid, a coil having a hollow center, a substantially C-shaped frame embracing said coil having a narrow opening atone end aligning with the hollow center of the coil, a plunger slide structure including a pair of spaced non-permeable, channel-shaped slides arranged in the opening of the frame and the hollow of the coil,

said slides having plunger supporting rails, a substantially T-shaped plunger, said plunger comprising an elongated stem reciprocable in said slides, a transversely'extending bar at the outer endof the stem, at second transversely extending bar along the sideeof the first mentioned bar facing the free end of the stem, said second bar having a length less than. the length of said first mentioned bar, and slots extending inwardly of said sec ond bar on opposite sides of the stern and paralleling Matthias Feb. 12, 1942 Seitzman Nov. 5, 1957 

